IRIS S550, Applications Manual, Page: 13 / 19

673 - 637
573 - 537
473 - 437
373 - 337
273 - 237
173 - 137
073 - 000
This approach makes a wide range available for
gain multi plier changes using the two least
significant digits. For example, over a range of
137 to 199 the gain is changed by a ratio of 99/37.
It is advan ta geous for moderate changes in gain to
change only the gain multi plier digits because the
response to these changes is very linear. When
changes are made in the most significant gain
digit, the gain change is not always exactly an
ideal 2:1 step change.
MAN UAL SETUP OF THE S550
The steps below for manual setup should result in
the P520 or P522 displaying a reading close to
1200 with flame on. This pro ce dure should pro -
vide similar gain settings for each selected sensor
as in the
CALIBRATION
pro ce dure described
earlier.
1) Bring the firing rate of the burner to a low fire
condition.
2) Be sure that the external input for CHAN SEL
is properly set for the channel calibration (A or
B) that is currently being set and the channel
LED is ON continu ously.
3) Decide whether to setup the S550 using the
UV or IR sensor bef ore aiming the viewing
head. In some flames the best UV reading of
the flame envelope may be found at a different
location from the best IR reading. See earlier
sections
IR DETECTOR
and
UV DETECTOR
.
Use the Adjust Mode (“AdJ?”) pro ce dure for
the S550 described above and set the gain for
the sensor not being used to zero.
4) If the IR sensor is being used, bef ore final
aiming but with a typical reading on the
display, verify that the S550 is not saturated by
reducing the IR gain by 100. The displayed
reading should be reduced by roughly 1/2. If it
stays the same or actually increases, the S550
is saturated. Continue reducing the gain in
steps of 100 until the displayed reading is
reduced. Then set the gain so the reading is in
the 1000 to 1400 range. If the IR sensor was
not saturated one can skip para graph 5) below.
5) If the S550 was saturating one should check
the aiming of the S550 again using the LED
on the back of the housing to adjust the
viewing angle of the head for a maximum
pulse rate. If the LED pulse rate is then too
high (the LED is ON almost continu ously)
change the gain once more by using the Adjust
Mode pro ce dure to get a reading in the 1000 to
1400 range. Then maximize the pulse rate by
re-aiming the S550 viewing head. This pro ce
-
dure of optimizing the sighting and adjusting
the gain may have to be done more than one
time to be assured that the S550 is properly
setup.
6) If the UV sensor has been chosen adjust the
gain (00-99) using the Adjust Mode so the
displayed reading is close to 1200. The UV
sensor is not likely to saturate but if the flame
signal readings are very high on low gain
settings then one should orifice the sighting.
See section
ORIFICING.
7) Set or at least check the Flame ON and Flame
OFF set points. If they are still at the factory
default values (Flame ON at 800 and Flame
OFF at 600) they may be satis factory as they
are. If the Flame ON reading is less than 1200
the Flame OFF setting should be propor tion
-
ately less.
8) Review the settings for F.F.R.T. and TIME
DELAY ON and adjust if necessary.
RE TURN TO DE FAULT SET TINGS
There are three major branches on the decision
tree after one gets into the S550 setup by pressing
the A and B push buttons. Ref er to Fig. 3 at the
end of this manual. That is, if one says NO to
“CAL?”, one is asked if one wishes to do adjust. If
one says NO to “AdJ?”, one is asked if one wishes
to go back to the default settings. If one says NO
to “dEF?”, then the P520/P522 and S550 continue
PAGE 13
IRIS MODEL S550 APPLICATION MANUAL